Electric motor regulation with controlled error intercept

• US 7,474,071 B2
• Filed: 09/19/2006
• Issued: 01/06/2009
• Est. Priority Date: 09/19/2005
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Infineon Technologies AG
• Inventors: Lipperer, Georg, Koeppl, Benno
• Primary Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US11/533,026
• Publication Number:
  US 20070069674A1
• Time in Patent Office: 840 Days
• Field of Search: 318/254, 318/432, 318/434, 318/489, 180/443, 180/444, 180/4, 701/41, 701/43
• US Class Current: 318/489
• CPC Class Codes: B62D 5/0484 for reaction to failures, e.g. limp home
• CPC Class Codes: H02H 7/0858 by reversing, cycling or reducing the power supply to the motor

Abstract

A motor is controlled by a motor control signal so that it reaches a target state, which is derived from sensor data sensed by a sensor. The motor can be put into a rest state at the occurrence of an error in simple and efficient manner by means of a safety means generating an alternative motor control signal at the occurrence of the error. Thus, the underlying idea is, instead of redundantly embodying components, to consciously accept a failure and integrate a corresponding fall-back solution into the overall concept. The failure is detected, and the motor is switched off in a user-manageable manner by a targeted shutdown.

Claims

1. A motor control apparatus to control a motor, comprising:

a sensor for outputting sensor data;

a controller for determining a target state of the motor depending on the sensor data, and for generating a motor control signal for controlling the motor depending on a deviation of a current state of the motor from the target state, to approximate the current state of the motor to the target state;

a monitor for outputting an error signal at an error of the sensor or the controller; and

a safety controller for generating, at the occurrence of an error signal, an alternative motor control signal suited to put the motor into a rest state in a controlled manner.

2. The apparatus of claim 1, wherein the motor is an electric assistance motor of an electrical steering assistance.

3. The apparatus of claim 1, wherein the safety controller is formed to generate the alternative motor control signal so that a motor control quantity is put from an initial control quantity value into a final control quantity value according to a predetermined emergency rule.

4. The apparatus of claim 3, wherein the motor control quantity is a current or a voltage.

5. The apparatus of claim 3, wherein the safety controller is formed to reduce a momentary current flow as a motor control quantity to zero according to a predetermined reduction rule.

6. The apparatus of claim 3, wherein the safety controller is formed to generate the motor control quantity by means of a pulse-width-modulated signal.

7. The apparatus of claim 1, wherein the sensor is a torque sensor for sensing a torque.

8. The apparatus of claim 7, wherein the torque sensor is formed to sense the torque occurring at the steering wheel of a vehicle.

9. The apparatus of claim 1, wherein the controller includes a calculating unit formed to calculate the motor control signal depending on the sensor data.

10. The apparatus of claim 9, wherein the calculating unit is a microcontroller or an FPGA.

11. The apparatus of claim 1, wherein the controller additionally comprises a motor control sensor circuitry for outputting control data describing the current state of the motor.

12. The apparatus of claim 11, wherein the motor control sensor circuitry comprises a Hall sensor to sense a magnetic field in the motor.

13. The apparatus of claim 11, wherein the motor control sensor circuitry comprises a rotor position sensor to sense a position of the rotor of the motor.

14. The apparatus of claim 11, wherein the motor control sensor circuitry comprises a current sensor to sense a supply current of the motor.

15. The apparatus of claim 11, wherein the motor control sensor circuitry comprises a back current sensor to sense a current flowing out of the motor.

16. The apparatus of claim 1, wherein the motor is a polyphase-driven electric motor.

17. A method of controlling a motor, comprising:

sensing sensor data;

determining a target state of the motor depending on the sensor data;

generating a motor control signal for controlling the motor depending on a deviation of the motor from the target state to approximate a current state of the motor to the target state;

outputting an error signal at an error; and

generating, at the occurrence of the error signal, an alternative motor control signal suited to put the motor into a rest state in a controlled manner.

18. A computer program product comprising a program code for performing, when executed on a computer, performs a method of controlling a motor, the method comprising:

sensing sensor data;

determining a target state of the motor depending on the sensor data;

generating a motor control signal for controlling the motor depending on a deviation of the motor from the target state to approximate a current state of the motor to the target state;

outputting an error signal at an error; and

generating, at the occurrence of the error signal, an alternative motor control signal suited to put the motor into a rest state in a controlled manner.

19. A method of controlling a motor, comprising the steps of:

determining a target state of the motor depending on sensor data,

generating a motor control signal for controlling the motor

depending on a deviation of a current state of the motor from the target state, to approximate the current state of the motor to the target state;

outputting an error signal at an error of the sensor or the controller; and

generating, at the occurrence of an error signal, an alternative motor control signal suited to put the motor into a rest state in a controlled manner.

20. The method of claim 19, comprising the steps of generating the alternative motor control signal so that a motor control quantity is put from an initial control quantity value into a final control quantity value according to a predetermined emergency rule.

21. The method of claim 20, wherein the motor control quantity is a current or a voltage.

22. The method of claim 21, comprising the step of reducing a momentary current flow as a motor control quantity to zero according to a predetermined reduction rule.

23. The method of claim 20, comprising the step of generating the motor control quantity by means of a pulse-width-modulated signal.

24. The method of claim 19, wherein the torque occurring at the steering wheel of a vehicle is determined.

25. The method of claim 19, wherein a magnetic field in the motor is determined.

26. The method of claim 19, wherein a position of the rotor of the motor is determined.

27. The method of claim 19, wherein a supply current of the motor is determined.

28. The method of claim 19, wherein a current flowing out of the motor is determined.